Sealing device

ABSTRACT

Apparatus for creating a seal between an axle journal and a bearing housing is disclosed, particularly for use in apparatus for dewatering or washing material suspensions. The apparatus includes a stator ring, a pair of diagonally disposed guide pins supporting the stator ring with respect to the bearing housing so that the stator ring can be angled in a plane with respect to the pair of guide pins, a sealing ring for creating a seal between the stator ring and the axle journal, a bellows for creating a seal between the bearing housing and the stator ring, and at least one resilient member for urging the stator ring in abutment against the sealing ring.

FIELD OF THE INVENTION

The present invention relates to a sealing device for sealing between abearing housing and an axle journal of a roll, the two bearing housingsfor the axle journal bearings being movable in a direction across theaxle.

The present invention also relates to a device for dewatering and/orwashing material suspensions (for example pulp suspensions), comprisingat least one cylindrical rotary roll, which is surrounded by a casingwith an inlet for the material suspension, and which against an elementforms an outlet gap for the egress of the material suspension, where theaxle journals of the roll are mounted in bearings supported by bearinghousings, which are movable for taking up variations in the width of theoutlet gap, and sealing devices are provided for sealing between thebearing housing and the axle journals.

BACKGROUND OF THE INVENTION

The prior art, such as Swedish Patent Nos. 504,011; 515,543; and 501,719show examples of dewatering devices, which comprise liquid permeablepress rolls with a nip formed between them for dewatering a materialsuspension of wood fiber pulp. The pulp suspension is supplied to aportion of the device, which is under pressure and surrounded by acasing, and the dewatered pulp egresses through the nip. The pulpsuspension usually is supplied either from above or from below, as canbe seen from these references. The width of the outlet gap can vary,depending on the properties of the suspension which can be differentalong the length of the roll, and thus the roll can be angled inrelation to the bearing housing. It may also be necessary to adjust thenip, i.e. to move at least one roll towards or away from the other roll,and during this movement the roll can be slightly angled. The pulpsuspension is aggressive, and if it leaks into the bearings, thebearings will be destroyed. The sealing against the bearings, therefore,is of vital importance and an essential risk factor for theaccessibility of the device.

Present dewatering devices use as sealing between the bearing housingand the axle stuffing boxes and V-ring sealings (of rubber). They do notwithstand, however, the aggressive environment of the pulp suspensionand are destroyed and lose their sealing capacity.

One object of the present invention is to provide a sealing device forsealing between a bearing housing and the axle journal of a roll, thetwo bearing housings of which for the axle journal bearings are movablein the direction across the axle, where this sealing device shall have along service life even in an aggressive environment, and which allowsthe axle to be slightly angled in a plane during the movement, and inwhich the sealing can also take up a certain degree of axial movement. Amore specific object of the present invention is, by providing improvedsealing devices, to increase the operational reliability of a device fordewatering and/or washing material suspensions, comprising at least onecylindrical rotary roll, which is surrounded by a casing with an inletfor the material suspension, and which against an element forms a gapfor the egress of pulp, and the axle journals of the roll are mounted inbearings supported by bearing housings movable in the direction acrossthe axle.

SUMMARY OF THE INVENTION

These and other objects have now been realized by the discovery ofapparatus for creating a seal between an axle journal and a bearinghousing for the axle journal, the axle journal being angularlydisplaceable in a plane relative to the bearing housing, the apparatuscomprising a stator ring, a pair of diagonally disposed guide pinssupporting the stator ring with respect to the bearing housing wherebythe stator ring can be angled in a plane with respect to the pair ofguide pins, a sealing ring for creating a seal between the stator ringand the axle journal, a bellows for creating a seal between the bearinghousing and the stator ring, and at least one resilient member forurging the stator ring in abutment against the sealing ring. Preferably,the bellows is rigidly mounted with respect to the stator ring and withrespect to the bearing housing, the bellows comprising a non-resilientmaterial. In another embodiment, the at least one resilient member isdisposed to act between the bearing housing and the stator ring. Inanother embodiment, the sealing ring is mounted for rotation with theaxle journal.

In accordance with the present invention, apparatus has also beendiscovered for dewatering or washing material suspensions comprising atleast one cylindrical rotary roll including a pair of axle journals, theat least one cylindrical rotary roll separated by a predetermined gapfrom a second element, a trough surrounding the at least one cylindricalrotary roll, the trough including an inlet for the material suspension,an outlet for the material suspension comprising the predetermined gap,a pair of bearing housings, a pair of bearings supported by the pair ofbearing housings, the pair of axle journals being mounted in the pair ofbearings, the pair of bearing housings being individually movablewhereby the at least one cylindrical rotary roll can be angularlydisplaced with respect to the pair of bearing housings, each of the pairof bearing housings including sealing means for creating a seal betweenthe pair of bearing housings and the pair of axle journals, the sealingmeans comprising a stator ring, a pair of diagonally disposed guide pinssupporting the stator ring with respect to the bearing housing, wherebythe stator ring can be angled in a plane with respect to the pair ofguide pins, a sealing ring for creating a seal between the stator ringand the axle journal, a bellows for creating a seal between the bearinghousing and the stator ring, and at least one resilient member forurging the stator ring in abutment against the sealing ring. In apreferred embodiment, at least one of the at least one cylindricalrotary roll and the second element is liquid permeable. In anotherembodiment, the second element comprises a second cylindrical rotaryroll.

BRIEF DESCRIPTION OF THE DRAWINGS

The present invention may be more fully appreciated with reference tothe following detailed description, which in turn refers to the Figures,in which:

FIG. 1 is a front, elevational, cross-sectional, partially schematicview illustrating in principle a dewatering device for use in the pulpindustry;

FIG. 2 is a top, elevational view of a pair of rolls with anintermediate gap in the device shown in FIG. 1;

FIG. 3 is a front, elevational, enlarged sectional view of the rollsshown in FIG. 1 taken along line 3-3 thereof;

FIG. 4 is a partial front, enlarged longitudinal view taken through oneaxle journal bearing of a roll used in accordance with the presentinvention;

FIG. 5 is a side, elevational, partial, enlarged view of the circledportion shown in FIG. 3;

FIG. 6 is a front, elevational, enlarged sectional view of the circleportion shown in FIG. 3; and

FIG. 7 is a front, elevational view showing a stator ring for use in thepresent invention.

DETAILED DESCRIPTION

Turning to the Figures, FIG. 1 shows a roller press intended for liquidtreatment, for example, for the washing and dewatering of materialsuspensions, such as, for example, fiber pulp suspensions. The rollerpress is described only roughly, because it is already known. Twocylindrical, rotary, liquid permeable rolls, 9 and 10, are partiallylocated in a trough 11, which is formed so, that a converging space 12is formed between the trough 11 and each of the rolls, 9 and 10. Eachspace 12 has an inlet 13 for the material suspension. Each space 12 canalso have inlets for treatment liquid. Between the rolls, 9 and 10, agap 14 is formed, a so-called press nip, through which the dewateredpulp passes. At the inlet 13 a longitudinal seal 19 is provided to sealbetween the trough 11 and the circumference of the rolls, 9 and 10, sothat the trough 11 forms a tight casing about the lower portions of therolls.

FIG. 2 shows schematically the two rolls, 9 and 10, with axle journals,21, 22, 23 and 24, seen from above. The Figure also shows the end walls,25 and 26, of the trough 11. In the end walls a bearing housing, 30 and57 and 31 and 58, is provided for each of the axle journals, 21, 22, 23and 24. The axle journals, 21, 22, 23 and 24, are mounted in bearings inthe bearing housings, 30 and 57 and 31 and 58, and sealing devices, 27and 27′, and 28 and 28′, respectively, seal between the axle journalsand the bearing housings. The bearing housings for the axle journals aremovable horizontally, so that the gap 14 between the rolls, 9 and 10,can be changed as will be described with reference to FIG. 3. The movingof the bearing housings, and thereby of the axle journals of the bearinghousings, can take place individually, and during the moving, therefore,the roll can be angled in relation to the bearing housing, as shown inFIG. 2, and the width of the gap 14 will then temporarily not be equalalong the entire roll length, as shown in FIG. 2. This subjects thesealing devices, 27, 27′, 28 and 28′, to large requirements.

FIG. 3 shows the end wall 25 and two bearing housings, 30 and 31, whichare horizontally slidable along guide surfaces, 32 and 33, in the endwall 25, as shown in FIG. 4. When the suspension passes the gap 14, aline load is obtained on the rolls. The line load can vary along thelength of the gap and over time. This is due to the fact that theproperties of the suspension vary, such as for example the fibernetwork. Considerable foreign matter can also enter the process and passthrough the gap 14. Hydraulic cylinders, 34 and 35, and 36 and 37,respectively, are provided to prevent a pre-determined level of the lineload to be exceeded. If this should happen, the dewatering arrangementcan be damaged. The stroke length of the hydraulic cylinders can be, forexample, 20 mm. The hydraulic cylinders for one roll, for example thehydraulic cylinders, 34 and 35, for the roll 9, can be replaced bystationary stops, if it is desired to guide the gap width (line load) byonly one roll.

FIG. 4 shows the bearing housing 31 with one bearing 38 for the axlejournal 23 and the sealing device 27, which seals between the bearinghousing and the axle journal. The bearing in the embodiment shown is ofa spherical type and, thus, can take up angle changes.

FIGS. 5 and 6 show on an enlarged scale the parts 5 and 6, respectively,in FIG. 4, with the sealing device 27. The sealing device 27 comprises astator ring 40, which is supported, for example, by two guide pins 41, asealing ring unit 47, a bellow means 56 and at least one resilientelement (in the embodiment shown the resilient element is a spring).

The sealing ring unit 47 is intended to be tight-sealing against theaxle journal 23, to rotate with the axle journal 23, and to seal againstthe stator ring 40. The sealing ring unit 47 in the embodiment showncomprises a holding ring 42, which is tight-sealing against the axlejournal 23 with an O-ring 43 and rotates with the roll by carryinglocking pins 44. The sealing ring unit 47 in the embodiment shown alsocomprises a sealing ring 55 of solid glide material, for examplegraphite, which is supported by the holding ring 42.

FIG. 7 shows an illustration in principle of the stator ring 40 with twofirst recesses 60 for the guide pins 41 and eight second recesses 61 forthe spring 48. The device shown thus comprises eight springs 48, but itmay, of course, comprise a greater or smaller number of springs 48. Thesprings 48 are located in the bearing housing 31 and act against thestator ring 40. The springs 48 are intended to take up relativemovements between the bearing housing 31 and the stator ring 40, and toensure that the stator ring abuts against the sealing unit 47. Thesealing can thus take up axial movement and can rise due to wear betweenrotary and stationary parts, and when different parts of the device areheated unequally rapidly, so that the parts will have a different heatexpansion.

The guide pins 41 are arranged diagonally and vertically in relation toeach other in the stator ring, and each guide pin 41 has at its frontend a top 45. Each guide pin 41 is slidable in its recess 60 in thestator ring 40. The top 45 and recess 60 are formed in such a way inrelation to each other that the stator ring 40 can be angled slightly inthe horizontal plane. The top 45 suitably is spherical.

The bellow means 56 is intended to take up relative movements betweenthe bearing housing 31 and the stator ring 40. The bellow means 56 istightly attached to the stator ring and to the bearing housing 31, inorder to seal therebetween, and comprises a bellows 50. The bellow means56 in the embodiment shown comprises, for the attachment of the bellows50 to the bearing housing, a bipartite outer ring 49 with a first ringportion 63, which is tightly attached to the bearing housing 31, and asecond ring portion 64, and the bellows 50, which is ring-shaped, isclamped between the first and second ring portion, 63 and 64, byexternal fastening means 65, for example screws. The bellow means 56further comprises an inner ring 66, which by inner fastening means 67tightly clamps the bellows 50 against the stator ring 40. As the bellowsis rigidly clamped at its outer edges (relative to the stator ring and,respectively, bearing housing), it need not be of resilient material(for example rubber), but can be of a more durable material, for examplePTFE, which is not destroyed by the aggressive environment, as forexample a pulp suspension. A conventional additional radial sealing 52is provided in the embodiment shown near the bearing at the axlejournal, in order to separate the oil in the bearing from the air-filledclosed space 53. The suspension in the trough is indicated in FIG. 5 bythe reference 54.

The dewatering means shown is only one example, and the dewatering meanscan thus be of a type other than the one shown. The material flowthrough the gap 14, for example, can be downward instead of upward. Thesealing device, of course, can be provided for use in means other thandewatering means.

In the embodiment shown the sealing device is arranged so that the axlecan be angled slightly in the horizontal plane. The sealing device, ofcourse, can also be arranged so that it allows angling in other planes,depending entirely on the type of means, in which the device shall beused.

Although the invention herein has been described with reference toparticular embodiments, it is to be understood that these embodimentsare merely illustrative of the principles and applications of thepresent invention. It is therefore to be understood that numerousmodifications may be made to the illustrative embodiments and that otherarrangements may be devised without departing from the spirit and scopeof the present invention as defined by the appended claims.

1. Apparatus for dewatering or washing material suspensions comprisingat least one cylindrical rotary roll including a pair of axle journals,said at least one cylindrical rotary roll separated by a predeterminedgap from a second element, a trough surrounding said at least onecylindrical rotary roll, said trough including an inlet for saidmaterial suspension, an outlet for said material suspension comprisingsaid predetermined gap, a pair of bearing housings, a pair of bearingssupported by said pair of bearing housings, said pair of axle journalsbeing mounted in said pair of bearings, said pair of bearing housingsbeing individually movable whereby said at least one cylindrical rotaryroll can be angularly displaced with respect to said pair of bearinghousings, each of said pair of bearing housings including a sealingmeans for creating a seal between said pair of bearing housings and saidpair of axle journals, said sealing means comprising a stator ring, apair of diagonally disposed guide pins supporting said stator ring withrespect to said bearing housing, whereby said stator ring can be angledin a plane with respect to said pair of guide pins, a sealing ring forcreating a seal between said stator ring and said axle journal, abellows for creating a seal between said bearing housing and said statorring, and at least one resilient member for urging said stator ring inabutment against said sealing ring.
 2. The apparatus of claim 1 whereinat least one of said at least one cylindrical rotary roll and saidsecond element is liquid permeable.
 3. The apparatus of claim 2 whereinsaid second element comprises a second cylindrical rotary roll.